Investigators are on the hunt for three potential witnesses who were in the area of the British Consulate yesterday when two crudely built bombs exploded in front of the building, sending shrapnel flying nearly 10 stories into the air and shattering a window but injuring no one.

Police Commissioner Ray Kelly said officials are reviewing 17 surveillance videos from 15 locations in surrounding Midtown buildings but said much of it was “fuzzy” and would need to be enhanced.

Kelly said a female jogger, a taxi-cab driver and a man on a bicycle were spotted in some of the footage around the time of the explosion and that investigators were looking to talk to them.

“At this time, we have no eyewitnesses, but we are looking for them,” Kelly said.

No group or individual claimed responsibility for the blast, which occurred just as the United Kingdom began a national election. Officials, however, said they could not be sure the explosion targeted the consulate, as the building is home to dozens of other offices.

“We don’t know who the particular target was at this time,” Mayor Bloomberg said after the explosion. “There were no threats or phone calls.”

U.S. counterterrorism officials doubted the blast was the work of an organized international terrorist group and were leaving the investigation in local hands.

At least one of the bombs, fashioned from two novelty grenades filled with black powder and lit by fuses, ripped through the side of a concrete planter at around 3:35 a.m. and shattered the front window of the building on 845 Third Ave., Kelly said.

The other grenade appeared to have been thrown, Kelly said, because in a surveillance video, a red streak is seen arcing through the air and then bouncing off the front of the building.

Shrapnel from one of the grenades was found across the street embedded in the facade on the ninth floor of 830 Third Ave., Kelly said.

“They were of considerable power and could have caused significant injuries if it was crowded at the time,” he said.

A 41-year-old U.N. weapons analyst from the Netherlands who was in the area following the blast and resisted police orders to leave was arrested and charged with obstructing governmental administration – but police said later he was ruled out as a suspect.

In Britain, citizens voted in a heated election in which Tony Blair’s bid for a third term had been hindered by rancor over the Iraq war.

British Consul-General Sir Philip Thomas reiterated that there was no evidence the consulate was the target of the attack but that officials were working with the NYPD as the investigation continued.

The consulate remained open yesterday, although investigators shut down numerous blocks surrounding the building, which also houses the New York offices of Japanese newspaper Asahi Shimbun and the Weather Channel, for several hours.

Kelly said investigators were also looking into a group that in April had protested outside the building, which houses the offices of a board member of the construction-vehicle company Caterpillar Inc.

The group decried the razing of homes in Palestinian territory and claimed Caterpillar supplied the vehicles for the demolition.

Later in the day, as activity returned to normal, many who work in the area appeared none too shaken by the early morning blast.

“I’m used to it,” said Marie, 28, an immigrant from Ireland who works around the corner at Doherty’s Pub. “When I was younger, it was commonplace back home. I’ve lived with it all my life.”

Additional reporting by John Doyle and Niles Lathem

—

Bang-up job

According to police, this is how the bomb that exploded in front of the British Consulate building yesterday